In this case, a developer wanted to get the 64-bit number from two 32-bit ones, having shifted 'x' for some number of bits 'shift' and having merged the small and the great part. It is possible that 'shift' may have the value equal to 32. As 'x' is 32-bit number at the moment of shifting, then a shift for 32 bits is equal to a shift for 0 bit, which will lead to incorrect result.